Dietary and Lifestyle Factors Modulate the Activity of the Endogenous Antioxidant System in Patients with Age-Related Macular Degeneration: Correlations with Disease Severity

Abstract

Age-related macular degeneration (AMD) is a common cause of blindness in the elderly population, but the pathogenesis of this disease remains largely unknown. Since oxidative stress is suggested to play a major role in AMD, we aimed to assess the activity levels of components of the antioxidant system in patients with AMD. We also investigated whether lifestyle and dietary factors modulate the activity of these endogenous antioxidants and clinical parameters of disease severity. We recruited 330 patients with AMD (39 with early, 100 with intermediate and 191 with late form of AMD) and 121 controls in this study. At enrolment, patients’ dietary habits and physical activity were assessed, and each study participant underwent a thorough ophthalmologic examination. The activity of several components of the antioxidant system were measured in red blood cells and platelets using both kinetic and spectrophotometric methods. Patients with AMD consumed much lower levels of fatty fish and eggs than the control group (p = 0.008 and p = 0.04, respectively). In the nAMD group, visual acuity (VA) correlated positively with green vegetable consumption (Rs = +0.24, p = 0.004) and omega-3-rich oil intake (Rs = +0.17, p = 0.03). In the AMD group, the total physical activity MET score correlated positively with VA (Rs = +0.17, p = 0.003) and correlated negatively with the severity of AMD (Rs = −0.14, p = 0.01). A multivariate analysis of patients and controls adjusted for age, sex, and smoking status (pack-years) revealed that AMD was an independent variable associated with a lower RBC catalase (β = −0.37, p < 0.001) and higher PLT catalase (β = +0.25, p < 0.001), RBC GPx (β = +0.26, p < 0.001), PLT GPx (β = +0.16, p = 0.001), RBC R-GSSG (β = +0.13, p = 0.009), PLT R-GSSG (β = +0.12, p = 0.02) and RBC GSH transferase (β = +0.23, p < 0.001) activity. The activities of components of the antioxidant system were associated with disease severity and depended on dietary habits. The observed substantial increase in the activity of many critical endogenous antioxidants in patients with AMD further indicates that the required equilibrium in the antioxidant system is disturbed throughout the course of the disease. Our findings explicitly show that a diet rich in green vegetables, fish and omega-3-rich oils, supplemented by physical exercise, is beneficial for patients with AMD, as it might delay disease progression and help retain better visual function.

The impact of vascular risk factors on the thickness and volume of the choroid in AMD patients

“…Finally, with the help of a member of the research team, each participant completed the International Physical Activity Questionnaire (IPAQ), comprising 7 questions regarding all types of physical activity (lasting 10 min or longer) in the previous week. Physical activity scores are presented as MET-min per week and were calculated as described previously 25 . In brief, each activity-specific factor was multiplied by the number of days spent performing the activity and the time in minutes spent performing the activity daily.…”

Antioxidant Activity and Neuroprotective Role of Docosahexaenoic Acid (DHA) Supplementation in Eye Diseases That Can Lead to Blindness: A Narrative Review

“…Similar studies of dietary supplementation with high-dose DHA-TG in age-related macular degeneration (AMD) have not been carried out, but results reported from a variety of research are inconsistent regarding the effects on omega-3 fatty acids on visual acuity, progression and development of drusen or the presence of geographic atrophy [ 57 ]. However, it has been reported that high erythrocyte content of EPA/DHA is a protective factor against AMD compared with permanently low EPA/DHA levels [ 58 ]. Results of the phase 3 randomized controlled AREDS2 study in which there was no overall additional benefit from adding n-3 PUFAS or lutein and zeaxanthin to the original AREDS formulation (vitamins C and E, beta-carotene, zinc oxide, cupric oxide) in reducing the risk of advanced AMD [ 59 ] merits a comment.…”

Anti‑inflammatory role of curcumin in retinal disorders (Review)

“…Currently, no treatment is reported to exist for the dry form, while the neovascular one is commonly approached with continued intraocular injections of anti-vascular endothelial growth factor (anti-VEGF) (38). To date, AMD pathogenesis remains unclear: Undoubtedly, inflammation and oxidative stress, along with other risk factors such as aging, smoking, sun exposure and a poor diet, play a major role in AMD (39). As is well-known, the macula is constantly exposed to both oxygen and light and, consequently, a great amount of ROS is produced in this region.…”